Visualization Library 2.0.0-b5

A lightweight C++ OpenGL middleware for 2D/3D graphics

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jdsample.c
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1 /*
2  * jdsample.c
3  *
4  * Copyright (C) 1991-1996, Thomas G. Lane.
5  * This file is part of the Independent JPEG Group's software.
6  * For conditions of distribution and use, see the accompanying README file.
7  *
8  * This file contains upsampling routines.
9  *
10  * Upsampling input data is counted in "row groups". A row group
11  * is defined to be (v_samp_factor * DCT_scaled_size / min_DCT_scaled_size)
12  * sample rows of each component. Upsampling will normally produce
13  * max_v_samp_factor pixel rows from each row group (but this could vary
14  * if the upsampler is applying a scale factor of its own).
15  *
16  * An excellent reference for image resampling is
17  * Digital Image Warping, George Wolberg, 1990.
18  * Pub. by IEEE Computer Society Press, Los Alamitos, CA. ISBN 0-8186-8944-7.
19  */
20 
21 #define JPEG_INTERNALS
22 #include "jinclude.h"
23 #include "jpeglib.h"
24 
25 
26 /* Pointer to routine to upsample a single component */
27 typedef JMETHOD(void, upsample1_ptr,
29  JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr));
30 
31 /* Private subobject */
32 
33 typedef struct {
34  struct jpeg_upsampler pub; /* public fields */
35 
36  /* Color conversion buffer. When using separate upsampling and color
37  * conversion steps, this buffer holds one upsampled row group until it
38  * has been color converted and output.
39  * Note: we do not allocate any storage for component(s) which are full-size,
40  * ie do not need rescaling. The corresponding entry of color_buf[] is
41  * simply set to point to the input data array, thereby avoiding copying.
42  */
43  JSAMPARRAY color_buf[MAX_COMPONENTS];
44 
45  /* Per-component upsampling method pointers */
46  upsample1_ptr methods[MAX_COMPONENTS];
47 
48  int next_row_out; /* counts rows emitted from color_buf */
49  JDIMENSION rows_to_go; /* counts rows remaining in image */
50 
51  /* Height of an input row group for each component. */
52  int rowgroup_height[MAX_COMPONENTS];
53 
54  /* These arrays save pixel expansion factors so that int_expand need not
55  * recompute them each time. They are unused for other upsampling methods.
56  */
57  UINT8 h_expand[MAX_COMPONENTS];
58  UINT8 v_expand[MAX_COMPONENTS];
59 } my_upsampler;
60 
61 typedef my_upsampler * my_upsample_ptr;
62 
63 
64 /*
65  * Initialize for an upsampling pass.
66  */
67 
68 METHODDEF(void)
70 {
71  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
72 
73  /* Mark the conversion buffer empty */
74  upsample->next_row_out = cinfo->max_v_samp_factor;
75  /* Initialize total-height counter for detecting bottom of image */
76  upsample->rows_to_go = cinfo->output_height;
77 }
78 
79 
80 /*
81  * Control routine to do upsampling (and color conversion).
82  *
83  * In this version we upsample each component independently.
84  * We upsample one row group into the conversion buffer, then apply
85  * color conversion a row at a time.
86  */
87 
88 METHODDEF(void)
90  JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
91  JDIMENSION in_row_groups_avail,
92  JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
93  JDIMENSION out_rows_avail)
94 {
95  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
96  int ci;
99 
100  /* Fill the conversion buffer, if it's empty */
101  if (upsample->next_row_out >= cinfo->max_v_samp_factor) {
102  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
103  ci++, compptr++) {
104  /* Invoke per-component upsample method. Notice we pass a POINTER
105  * to color_buf[ci], so that fullsize_upsample can change it.
106  */
107  (*upsample->methods[ci]) (cinfo, compptr,
108  input_buf[ci] + (*in_row_group_ctr * upsample->rowgroup_height[ci]),
109  upsample->color_buf + ci);
110  }
111  upsample->next_row_out = 0;
112  }
113 
114  /* Color-convert and emit rows */
115 
116  /* How many we have in the buffer: */
117  num_rows = (JDIMENSION) (cinfo->max_v_samp_factor - upsample->next_row_out);
118  /* Not more than the distance to the end of the image. Need this test
119  * in case the image height is not a multiple of max_v_samp_factor:
120  */
121  if (num_rows > upsample->rows_to_go)
122  num_rows = upsample->rows_to_go;
123  /* And not more than what the client can accept: */
124  out_rows_avail -= *out_row_ctr;
125  if (num_rows > out_rows_avail)
126  num_rows = out_rows_avail;
127 
128  (*cinfo->cconvert->color_convert) (cinfo, upsample->color_buf,
129  (JDIMENSION) upsample->next_row_out,
130  output_buf + *out_row_ctr,
131  (int) num_rows);
132 
133  /* Adjust counts */
134  *out_row_ctr += num_rows;
135  upsample->rows_to_go -= num_rows;
136  upsample->next_row_out += num_rows;
137  /* When the buffer is emptied, declare this input row group consumed */
138  if (upsample->next_row_out >= cinfo->max_v_samp_factor)
139  (*in_row_group_ctr)++;
140 }
141 
142 
143 /*
144  * These are the routines invoked by sep_upsample to upsample pixel values
145  * of a single component. One row group is processed per call.
146  */
147 
148 
149 /*
150  * For full-size components, we just make color_buf[ci] point at the
151  * input buffer, and thus avoid copying any data. Note that this is
152  * safe only because sep_upsample doesn't declare the input row group
153  * "consumed" until we are done color converting and emitting it.
154  */
155 
156 METHODDEF(void)
158  JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
159 {
160  *output_data_ptr = input_data;
161 }
162 
163 
164 /*
165  * This is a no-op version used for "uninteresting" components.
166  * These components will not be referenced by color conversion.
167  */
168 
169 METHODDEF(void)
171  JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
172 {
173  *output_data_ptr = NULL; /* safety check */
174 }
175 
176 
177 /*
178  * This version handles any integral sampling ratios.
179  * This is not used for typical JPEG files, so it need not be fast.
180  * Nor, for that matter, is it particularly accurate: the algorithm is
181  * simple replication of the input pixel onto the corresponding output
182  * pixels. The hi-falutin sampling literature refers to this as a
183  * "box filter". A box filter tends to introduce visible artifacts,
184  * so if you are actually going to use 3:1 or 4:1 sampling ratios
185  * you would be well advised to improve this code.
186  */
187 
188 METHODDEF(void)
190  JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
191 {
192  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
193  JSAMPARRAY output_data = *output_data_ptr;
194  register JSAMPROW inptr, outptr;
195  register JSAMPLE invalue;
196  register int h;
197  JSAMPROW outend;
198  int h_expand, v_expand;
199  int inrow, outrow;
200 
201  h_expand = upsample->h_expand[compptr->component_index];
202  v_expand = upsample->v_expand[compptr->component_index];
203 
204  inrow = outrow = 0;
205  while (outrow < cinfo->max_v_samp_factor) {
206  /* Generate one output row with proper horizontal expansion */
207  inptr = input_data[inrow];
208  outptr = output_data[outrow];
209  outend = outptr + cinfo->output_width;
210  while (outptr < outend) {
211  invalue = *inptr++; /* don't need GETJSAMPLE() here */
212  for (h = h_expand; h > 0; h--) {
213  *outptr++ = invalue;
214  }
215  }
216  /* Generate any additional output rows by duplicating the first one */
217  if (v_expand > 1) {
218  jcopy_sample_rows(output_data, outrow, output_data, outrow+1,
219  v_expand-1, cinfo->output_width);
220  }
221  inrow++;
222  outrow += v_expand;
223  }
224 }
225 
226 
227 /*
228  * Fast processing for the common case of 2:1 horizontal and 1:1 vertical.
229  * It's still a box filter.
230  */
231 
232 METHODDEF(void)
234  JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
235 {
236  JSAMPARRAY output_data = *output_data_ptr;
237  register JSAMPROW inptr, outptr;
238  register JSAMPLE invalue;
239  JSAMPROW outend;
240  int inrow;
241 
242  for (inrow = 0; inrow < cinfo->max_v_samp_factor; inrow++) {
243  inptr = input_data[inrow];
244  outptr = output_data[inrow];
245  outend = outptr + cinfo->output_width;
246  while (outptr < outend) {
247  invalue = *inptr++; /* don't need GETJSAMPLE() here */
248  *outptr++ = invalue;
249  *outptr++ = invalue;
250  }
251  }
252 }
253 
254 
255 /*
256  * Fast processing for the common case of 2:1 horizontal and 2:1 vertical.
257  * It's still a box filter.
258  */
259 
260 METHODDEF(void)
262  JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
263 {
264  JSAMPARRAY output_data = *output_data_ptr;
265  register JSAMPROW inptr, outptr;
266  register JSAMPLE invalue;
267  JSAMPROW outend;
268  int inrow, outrow;
269 
270  inrow = outrow = 0;
271  while (outrow < cinfo->max_v_samp_factor) {
272  inptr = input_data[inrow];
273  outptr = output_data[outrow];
274  outend = outptr + cinfo->output_width;
275  while (outptr < outend) {
276  invalue = *inptr++; /* don't need GETJSAMPLE() here */
277  *outptr++ = invalue;
278  *outptr++ = invalue;
279  }
280  jcopy_sample_rows(output_data, outrow, output_data, outrow+1,
281  1, cinfo->output_width);
282  inrow++;
283  outrow += 2;
284  }
285 }
286 
287 
288 /*
289  * Fancy processing for the common case of 2:1 horizontal and 1:1 vertical.
290  *
291  * The upsampling algorithm is linear interpolation between pixel centers,
292  * also known as a "triangle filter". This is a good compromise between
293  * speed and visual quality. The centers of the output pixels are 1/4 and 3/4
294  * of the way between input pixel centers.
295  *
296  * A note about the "bias" calculations: when rounding fractional values to
297  * integer, we do not want to always round 0.5 up to the next integer.
298  * If we did that, we'd introduce a noticeable bias towards larger values.
299  * Instead, this code is arranged so that 0.5 will be rounded up or down at
300  * alternate pixel locations (a simple ordered dither pattern).
301  */
302 
303 METHODDEF(void)
305  JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
306 {
307  JSAMPARRAY output_data = *output_data_ptr;
308  register JSAMPROW inptr, outptr;
309  register int invalue;
310  register JDIMENSION colctr;
311  int inrow;
312 
313  for (inrow = 0; inrow < cinfo->max_v_samp_factor; inrow++) {
314  inptr = input_data[inrow];
315  outptr = output_data[inrow];
316  /* Special case for first column */
317  invalue = GETJSAMPLE(*inptr++);
318  *outptr++ = (JSAMPLE) invalue;
319  *outptr++ = (JSAMPLE) ((invalue * 3 + GETJSAMPLE(*inptr) + 2) >> 2);
320 
321  for (colctr = compptr->downsampled_width - 2; colctr > 0; colctr--) {
322  /* General case: 3/4 * nearer pixel + 1/4 * further pixel */
323  invalue = GETJSAMPLE(*inptr++) * 3;
324  *outptr++ = (JSAMPLE) ((invalue + GETJSAMPLE(inptr[-2]) + 1) >> 2);
325  *outptr++ = (JSAMPLE) ((invalue + GETJSAMPLE(*inptr) + 2) >> 2);
326  }
327 
328  /* Special case for last column */
329  invalue = GETJSAMPLE(*inptr);
330  *outptr++ = (JSAMPLE) ((invalue * 3 + GETJSAMPLE(inptr[-1]) + 1) >> 2);
331  *outptr++ = (JSAMPLE) invalue;
332  }
333 }
334 
335 
336 /*
337  * Fancy processing for the common case of 2:1 horizontal and 2:1 vertical.
338  * Again a triangle filter; see comments for h2v1 case, above.
339  *
340  * It is OK for us to reference the adjacent input rows because we demanded
341  * context from the main buffer controller (see initialization code).
342  */
343 
344 METHODDEF(void)
346  JSAMPARRAY input_data, JSAMPARRAY * output_data_ptr)
347 {
348  JSAMPARRAY output_data = *output_data_ptr;
349  register JSAMPROW inptr0, inptr1, outptr;
350 #if BITS_IN_JSAMPLE == 8
351  register int thiscolsum, lastcolsum, nextcolsum;
352 #else
353  register INT32 thiscolsum, lastcolsum, nextcolsum;
354 #endif
355  register JDIMENSION colctr;
356  int inrow, outrow, v;
357 
358  inrow = outrow = 0;
359  while (outrow < cinfo->max_v_samp_factor) {
360  for (v = 0; v < 2; v++) {
361  /* inptr0 points to nearest input row, inptr1 points to next nearest */
362  inptr0 = input_data[inrow];
363  if (v == 0) /* next nearest is row above */
364  inptr1 = input_data[inrow-1];
365  else /* next nearest is row below */
366  inptr1 = input_data[inrow+1];
367  outptr = output_data[outrow++];
368 
369  /* Special case for first column */
370  thiscolsum = GETJSAMPLE(*inptr0++) * 3 + GETJSAMPLE(*inptr1++);
371  nextcolsum = GETJSAMPLE(*inptr0++) * 3 + GETJSAMPLE(*inptr1++);
372  *outptr++ = (JSAMPLE) ((thiscolsum * 4 + 8) >> 4);
373  *outptr++ = (JSAMPLE) ((thiscolsum * 3 + nextcolsum + 7) >> 4);
374  lastcolsum = thiscolsum; thiscolsum = nextcolsum;
375 
376  for (colctr = compptr->downsampled_width - 2; colctr > 0; colctr--) {
377  /* General case: 3/4 * nearer pixel + 1/4 * further pixel in each */
378  /* dimension, thus 9/16, 3/16, 3/16, 1/16 overall */
379  nextcolsum = GETJSAMPLE(*inptr0++) * 3 + GETJSAMPLE(*inptr1++);
380  *outptr++ = (JSAMPLE) ((thiscolsum * 3 + lastcolsum + 8) >> 4);
381  *outptr++ = (JSAMPLE) ((thiscolsum * 3 + nextcolsum + 7) >> 4);
382  lastcolsum = thiscolsum; thiscolsum = nextcolsum;
383  }
384 
385  /* Special case for last column */
386  *outptr++ = (JSAMPLE) ((thiscolsum * 3 + lastcolsum + 8) >> 4);
387  *outptr++ = (JSAMPLE) ((thiscolsum * 4 + 7) >> 4);
388  }
389  inrow++;
390  }
391 }
392 
393 
394 /*
395  * Module initialization routine for upsampling.
396  */
397 
398 GLOBAL(void)
400 {
401  my_upsample_ptr upsample;
402  int ci;
404  boolean need_buffer, do_fancy;
405  int h_in_group, v_in_group, h_out_group, v_out_group;
406 
407  upsample = (my_upsample_ptr)
408  (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
409  SIZEOF(my_upsampler));
410  cinfo->upsample = (struct jpeg_upsampler *) upsample;
411  upsample->pub.start_pass = start_pass_upsample;
412  upsample->pub.upsample = sep_upsample;
413  upsample->pub.need_context_rows = FALSE; /* until we find out differently */
414 
415  if (cinfo->CCIR601_sampling) /* this isn't supported */
416  ERREXIT(cinfo, JERR_CCIR601_NOTIMPL);
417 
418  /* jdmainct.c doesn't support context rows when min_DCT_scaled_size = 1,
419  * so don't ask for it.
420  */
421  do_fancy = cinfo->do_fancy_upsampling && cinfo->min_DCT_scaled_size > 1;
422 
423  /* Verify we can handle the sampling factors, select per-component methods,
424  * and create storage as needed.
425  */
426  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
427  ci++, compptr++) {
428  /* Compute size of an "input group" after IDCT scaling. This many samples
429  * are to be converted to max_h_samp_factor * max_v_samp_factor pixels.
430  */
431  h_in_group = (compptr->h_samp_factor * compptr->DCT_scaled_size) /
432  cinfo->min_DCT_scaled_size;
433  v_in_group = (compptr->v_samp_factor * compptr->DCT_scaled_size) /
434  cinfo->min_DCT_scaled_size;
435  h_out_group = cinfo->max_h_samp_factor;
436  v_out_group = cinfo->max_v_samp_factor;
437  upsample->rowgroup_height[ci] = v_in_group; /* save for use later */
438  need_buffer = TRUE;
439  if (! compptr->component_needed) {
440  /* Don't bother to upsample an uninteresting component. */
441  upsample->methods[ci] = noop_upsample;
442  need_buffer = FALSE;
443  } else if (h_in_group == h_out_group && v_in_group == v_out_group) {
444  /* Fullsize components can be processed without any work. */
445  upsample->methods[ci] = fullsize_upsample;
446  need_buffer = FALSE;
447  } else if (h_in_group * 2 == h_out_group &&
448  v_in_group == v_out_group) {
449  /* Special cases for 2h1v upsampling */
450  if (do_fancy && compptr->downsampled_width > 2)
451  upsample->methods[ci] = h2v1_fancy_upsample;
452  else
453  upsample->methods[ci] = h2v1_upsample;
454  } else if (h_in_group * 2 == h_out_group &&
455  v_in_group * 2 == v_out_group) {
456  /* Special cases for 2h2v upsampling */
457  if (do_fancy && compptr->downsampled_width > 2) {
458  upsample->methods[ci] = h2v2_fancy_upsample;
459  upsample->pub.need_context_rows = TRUE;
460  } else
461  upsample->methods[ci] = h2v2_upsample;
462  } else if ((h_out_group % h_in_group) == 0 &&
463  (v_out_group % v_in_group) == 0) {
464  /* Generic integral-factors upsampling method */
465  upsample->methods[ci] = int_upsample;
466  upsample->h_expand[ci] = (UINT8) (h_out_group / h_in_group);
467  upsample->v_expand[ci] = (UINT8) (v_out_group / v_in_group);
468  } else
469  ERREXIT(cinfo, JERR_FRACT_SAMPLE_NOTIMPL);
470  if (need_buffer) {
471  upsample->color_buf[ci] = (*cinfo->mem->alloc_sarray)
472  ((j_common_ptr) cinfo, JPOOL_IMAGE,
473  (JDIMENSION) jround_up((long) cinfo->output_width,
474  (long) cinfo->max_h_samp_factor),
475  (JDIMENSION) cinfo->max_v_samp_factor);
476  }
477  }
478 }
char JSAMPLE
Definition: jmorecfg.h:64
start_pass_upsample(j_decompress_ptr cinfo)
Definition: jdsample.c:69
noop_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
Definition: jdsample.c:170
JDIMENSION downsampled_width
Definition: jpeglib.h:154
JSAMPLE FAR * JSAMPROW
Definition: jpeglib.h:66
#define NULL
Definition: ftobjs.h:61
struct jpeg_common_struct * j_common_ptr
Definition: jpeglib.h:261
GLfloat GLfloat GLfloat GLfloat h
h2v1_fancy_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
Definition: jdsample.c:304
#define MAX_COMPONENTS
Definition: jmorecfg.h:35
#define GETJSAMPLE(value)
Definition: jmorecfg.h:68
#define ERREXIT(cinfo, code)
Definition: jerror.h:205
#define SIZEOF(object)
Definition: jinclude.h:80
jinit_upsampler(j_decompress_ptr cinfo)
Definition: jdsample.c:399
boolean component_needed
Definition: jpeglib.h:160
my_upsampler * my_upsample_ptr
Definition: jdmerge.c:70
long INT32
Definition: jmorecfg.h:164
jpeg_component_info * compptr
Definition: jdct.h:102
#define JPOOL_IMAGE
Definition: jpeglib.h:749
jround_up(long a, long b)
Definition: jutils.c:81
short UINT8
Definition: jmorecfg.h:140
int_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
Definition: jdsample.c:189
int JSAMPARRAY int int num_rows
Definition: jpegint.h:373
const GLdouble * v
typedef long(ZCALLBACK *tell_file_func) OF((voidpf opaque
JSAMPARRAY * JSAMPIMAGE
Definition: jpeglib.h:68
#define FALSE
Definition: ftobjs.h:57
JSAMPROW * JSAMPARRAY
Definition: jpeglib.h:67
if(!abbox) return FT_THROW(Invalid_Argument)
typedef int
Definition: png.h:978
my_upsampler * my_upsample_ptr
Definition: jdsample.c:61
#define GLOBAL(type)
Definition: jmorecfg.h:191
#define METHODDEF(type)
Definition: jmorecfg.h:187
h2v2_fancy_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
Definition: jdsample.c:345
sep_upsample(j_decompress_ptr cinfo, JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, JDIMENSION in_row_groups_avail, JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, JDIMENSION out_rows_avail)
Definition: jdsample.c:89
jpeg_component_info JCOEFPTR JSAMPARRAY output_buf
Definition: jdct.h:102
unsigned int JDIMENSION
Definition: jmorecfg.h:174
h2v2_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
Definition: jdsample.c:261
h2v1_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
Definition: jdsample.c:233
fullsize_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
Definition: jdsample.c:157
jcopy_sample_rows(JSAMPARRAY input_array, int source_row, JSAMPARRAY output_array, int dest_row, int num_rows, JDIMENSION num_cols)
Definition: jutils.c:111
#define TRUE
Definition: ftobjs.h:53
typedef JMETHOD(void, upsample1_ptr,(j_decompress_ptr cinfo, jpeg_component_info *compptr, JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr))